Field of the Invention
Embodiments of the invention relate to a display device having a flexible film cable.
Discussion of the Related Art
Examples of a flat panel display include a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting display, and an electrophoresis display (EPD). The liquid crystal display displays an image by controlling an electric field applied to liquid crystal molecules based on a data voltage. An active matrix liquid crystal display has advantages of a reduction in the production cost and an improvement of a performance with the development of the process technology and the driving technology, and thus is the most widely used display device applied to almost all display devices including small mobile equipments and large-sized televisions.
Because the organic light emitting display is a self-emitting device, it has lower power consumption and thinner profile than the liquid crystal display requiring a backlight unit. Further, the organic light emitting display has advantages of a wide viewing angle and a fast response time. Thus, the organic light emitting display has been considered as a next generation display device capable of replacing the liquid crystal display.
Each pixel of the organic light emitting display includes an organic light emitting diode (OLED) having a self-emitting structure. The OLED includes organic compound layers such as a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, and an electron injection layer. The OLED emits light when electrons and holes are combined in an organic layer through a current flowing in a fluorescence or phosphorescence organic thin film.
The organic light emitting display requires display panel driving circuits including source driver integrated circuits (ICs) for generating a data voltage, gate driver ICs for generating a gate pulse (or scan pulse) synchronized with the data voltage, a timing controller for controlling operation timings of the source driver ICs and the gate driver ICs, etc. The timing controller transmits digital video data of an input image to the source driver ICs. The timing controller generates a source timing control signal for controlling the operation timing of the source driver ICs and a gate timing control signal for controlling the operation timing of the gate driver ICs. The gate timing control signal may be transmitted to the gate driver ICs through a flexible circuit substrate such as a flexible flat cable (FFC) and a flexible printed circuit (FPC). The FPC is manually inserted into a connector installed in a printed circuit board (PCB) and thus is connected to the PCB. The FPC may be bonded to a display panel through an anisotropic conductive film (ACF). Further, the FPC may be bonded to the PCB and the display panel through the ACF. Both terminals of the FPC are connected to each other through a connector. Thus, when a source PCB is connected to a gate PCB, the FPC is connected to a connector mounted on the source PCB and a connector mounted on the gate PCB.
The flexible circuit substrate such as the FFC and the FPC has a multi-layered bonding structure, in which films each having a thick thickness of about 300 μm to 350 μm and the large modulus of elasticity are bonded to one another. Hence, when the PCB is disposed in the rear of the display panel by bending the flexible circuit substrate, a crack may be generated in the flexible circuit substrate or in a bonding surface between the FFC or the FPC and the display panel. Thus, when the flexible circuit substrate is bonded to the display panel and is bent, a defective rate of the flexible circuit substrate increases.
A high potential pixel power voltage EVDD and a low potential pixel power voltage EVSS are supplied to the pixels of the organic light emitting display. However, if EVDD lines for supplying the high potential pixel power voltage EVDD and EVSS lines for supplying the low potential pixel power voltage EVSS are short-circuited, a burnt out may be generated in a short-circuited portion.